/*
 * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 * $Id: XPathFilterParameterSpec.java,v 1.4 2005/05/10 16:40:17 mullan Exp $
 */
package javax.xml.crypto.dsig.spec;

import javax.xml.crypto.dsig.Transform;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Parameters for the <a href="http://www.w3.org/TR/xmldsig-core/#sec-XPath">
 * XPath Filtering Transform Algorithm</a>.
 * The parameters include the XPath expression and an optional <code>Map</code>
 * of additional namespace prefix mappings. The XML Schema Definition of
 * the XPath Filtering transform parameters is defined as:
 * <pre><code>
 * &lt;element name="XPath" type="string"/&gt;
 * </code></pre>
 *
 * @author Sean Mullan
 * @author JSR 105 Expert Group
 * @see Transform
 * @since 1.6
 */
public final class XPathFilterParameterSpec implements TransformParameterSpec {

  private String xPath;
  private Map<String, String> nsMap;

  /**
   * Creates an <code>XPathFilterParameterSpec</code> with the specified
   * XPath expression.
   *
   * @param xPath the XPath expression to be evaluated
   * @throws NullPointerException if <code>xPath</code> is <code>null</code>
   */
  public XPathFilterParameterSpec(String xPath) {
    if (xPath == null) {
      throw new NullPointerException();
    }
    this.xPath = xPath;
    this.nsMap = Collections.emptyMap();
  }

  /**
   * Creates an <code>XPathFilterParameterSpec</code> with the specified
   * XPath expression and namespace map. The map is copied to protect against
   * subsequent modification.
   *
   * @param xPath the XPath expression to be evaluated
   * @param namespaceMap the map of namespace prefixes. Each key is a namespace prefix
   * <code>String</code> that maps to a corresponding namespace URI <code>String</code>.
   * @throws NullPointerException if <code>xPath</code> or <code>namespaceMap</code> are
   * <code>null</code>
   * @throws ClassCastException if any of the map's keys or entries are not of type
   * <code>String</code>
   */
  @SuppressWarnings("rawtypes")
  public XPathFilterParameterSpec(String xPath, Map namespaceMap) {
    if (xPath == null || namespaceMap == null) {
      throw new NullPointerException();
    }
    this.xPath = xPath;
    Map<?, ?> copy = new HashMap<>((Map<?, ?>) namespaceMap);
    Iterator<? extends Map.Entry<?, ?>> entries = copy.entrySet().iterator();
    while (entries.hasNext()) {
      Map.Entry<?, ?> me = entries.next();
      if (!(me.getKey() instanceof String) ||
          !(me.getValue() instanceof String)) {
        throw new ClassCastException("not a String");
      }
    }

    @SuppressWarnings("unchecked")
    Map<String, String> temp = (Map<String, String>) copy;

    nsMap = Collections.unmodifiableMap(temp);
  }

  /**
   * Returns the XPath expression to be evaluated.
   *
   * @return the XPath expression to be evaluated
   */
  public String getXPath() {
    return xPath;
  }

  /**
   * Returns a map of namespace prefixes. Each key is a namespace prefix
   * <code>String</code> that maps to a corresponding namespace URI
   * <code>String</code>.
   * <p>
   * This implementation returns an {@link Collections#unmodifiableMap
   * unmodifiable map}.
   *
   * @return a <code>Map</code> of namespace prefixes to namespace URIs (may be empty, but never
   * <code>null</code>)
   */
  @SuppressWarnings("rawtypes")
  public Map getNamespaceMap() {
    return nsMap;
  }
}
